The terms 32-bit and 64-bit refer to the way a computer's processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of random access memory (RAM) more effectively than a 32-bit system.

To install a 64-bit version of Windows 7, you need a CPU that's capable of running a 64-bit version of Windows. The benefits of using a 64-bit operating system are most apparent when you have a large amount of random access memory (RAM) installed on your computer, typically 4 GB of RAM or more. In such cases, because a 64-bit operating system can handle large amounts of memory more efficiently than a 32-bit operating system, a 64-bit system can be more responsive when running several programs at the same time and switching between them frequently. For more information, see Installing and reinstalling Windows 7‍.

To run a 64-bit version of Windows, your computer must have a 64-bit-capable processor. To find out if your processor is 64-bit-capable in Windows 7 or Windows Vista, do the following:

Open Performance Information and Tools by clicking the Start button , and then clicking Control Panel. In the search box, type Performance Information and Tools, and then, in the list of results, click Performance Information and Tools.

Do one of the following:

In Windows 7, click View and print detailed performance and system information.

In Windows Vista, click View and print details.

In the System section, you can see what type of operating system you're currently running under System type, and whether or not you can run a 64-bit version of Windows under 64-bit capable. (If your computer is already running a 64-bit version of Windows, you won't see the 64-bit capable listing.)

To see whether a computer running Windows XP is capable of running a 64-bit version of Windows, do the following:

Click Start.

Right-click My Computer, and then click Properties.

If "x64 Edition" is listed under System, your processor is capable of running a 64-bit version of Windows.

If you don't see "x64 Edition" listed, your processor still might be capable of running a 64-bit version of Windows. To find out for sure, download and run the free Windows 7 Upgrade Advisor from the Windows 7 Upgrade Advisor webpage.

You can use the Upgrade option during Windows 7 installation, which preserves your files, settings, and programs, only if you're currently running a 32-bit version of Windows Vista and you want to upgrade to the 32-bit version of Windows 7. Similarly, if you are running a 64-bit version of Windows Vista, you can only perform an upgrade to a 64-bit version of Windows 7. For more information, go to Upgrading to Windows 7: frequently asked questions on the Windows website.

If you want to move from a 32-bit version of Windows to a 64-bit version of Windows 7 or vice versa, you'll need to back up your files and choose the Custom option during Windows 7 installation. Then, you'll need to restore your files and reinstall your programs. For more information about performing a custom installation, see Installing and reinstalling Windows 7‍.

Notes

To install a 64-bit version of Windows 7 on a computer running a 32-bit version of Windows, you'll need to start, or boot, your computer using a 64-bit Windows 7 installation disc or files.

If you start your computer using a 64-bit Windows 7 installation disc or files, but your computer isn't capable of running a 64-bit version of Windows, you'll see a Windows Boot Manager error. You'll need to use a 32-bit Windows 7 installation disc or files instead.

Windows Easy Transfer can't transfer files from a 64-bit version of Windows to a 32-bit version of Windows. If you're running a 64-bit version of Windows Vista but you plan to install a 32-bit version of Windows 7, you can move your files to an external location manually or use Backup and Restore in Windows Vista. For more information, go to Back up your files and Restore a backup created on a previous version of Windows on the Windows website. (If you're running a 64-bit version of Windows XP, you'll need to move your files to an external location manually.)

Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.

Device drivers designed for the 32-bit version of Windows don't work on computers running a 64-bit version of Windows. If you're trying to install a printer or other device that only has 32-bit drivers available, it won't work correctly on a 64-bit version of Windows. To learn how to check for drivers, see Update a driver for hardware that isn't working properly or go to the device manufacturer's website. You can also get information about drivers by going to the Windows 7 Upgrade Advisor webpage.

If the program is specifically designed for the 64-bit version of Windows, it won't work on the 32-bit version of Windows. (However, most programs designed for the 32-bit version of Windows do work on the 64-bit version of Windows.)

To find programs and devices that work with Windows 7, look for products that display the "Compatible with Windows 7" logo. They've been tested to be compatible with both the 32-bit and 64-bit versions of Windows 7.

You can also go online to the Windows 7 Compatibility Center and check to see whether the program or device is compatible with the 64-bit version of Windows 7. Hardware and software manufacturers continue to update this information, so check back often.

To install a 64-bit version of Windows Vista, you need a processor that's capable of running a 64-bit version of Windows. The benefits of using a 64-bit operating system are most apparent when you have a large amount of random access memory (RAM) installed on your computer (typically 4 GB of RAM or more). In such cases, because a 64-bit operating system can handle large amounts of memory more efficiently than a 32-bit operating system, a 64-bit operating system can be more responsive when running several programs at the same time and switching between them frequently.

To run a 64-bit version of Windows, your computer must have a 64-bit-capable processor. To find out if your processor is 64-bit-capable, do the following:

Open Performance Information and Tools by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking Performance Information and Tools.

Click View and print details.

In the System section, you can see what type of operating system you're currently running under System type. Under 64-bit capable, you can see whether you can run a 64-bit version of Windows. (If your computer is already running a 64-bit version of Windows, you won't see the 64-bit capable listing.)

No. If you are currently running a 32-bit version of Windows, you can only perform an upgrade to another 32-bit version of Windows. Similarly, if you are running a 64-bit version of Windows, you can only perform an upgrade to another 64-bit version of Windows.

If you want to move from a 32-bit version of Windows to a 64-bit version of Windows Vista or vice versa, you'll need to back up your files and then choose the Custom option during Windows Vista installation. Then, you'll need to restore your files and reinstall your programs. For more information, see Installing and reinstalling Windows Vista.

Notes

To install a 64-bit version of Windows on a computer running a 32-bit version of Windows, you'll need to start, or boot, your computer using a 64-bit Windows installation disc.

If you start your computer using a 64-bit Windows installation disc, but your computer isn't capable of running a 64-bit version of Windows, you'll see a Windows Boot Manager error. You'll need to use a 32-bit Windows installation disc instead.

Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.

Device drivers designed for 32-bit versions of Windows won't work on computers running a 64-bit version of Windows. If you're trying to install a printer or other device that only has 32-bit drivers available, it won't work correctly on a 64-bit version of Windows. If you are unsure whether there is a 64-bit driver available for your device, go online to the Windows Vista Compatibility Center.

If the program is specifically designed for the 64-bit version of Windows, it won't work on the 32-bit version of Windows. (However, most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows.)